“…The most frequent external variables identified in the literature include lack of mentoring and sponsorship (Hom et al, 2008;Meyers, 2015;McDonald and Westphal, 2013), exclusion from informal networks (Cook and Glass, 2014;Fain, 2011;Kulich et al, 2015), lack of flexibility (Klettner et al, 2016;Waumsley and Houston, 2009;Williams et al, 2013), motherhood penalties (Budig et al, 2012;Kmec et al, 2014;Kricheli-Katz, 2012;Stone and Hernandez, 2013), gender stereotyping (Burke and Major, 2014;Branson et al, 2013;Heilman, 2001), the male-centered work ethos (Cahusac and Kanji, 2014;Cabrera, 2009;Kelly et al, 2010;Widera et al, 2010) and the glass ceiling (Cook and Glass, 2014;Fain, 2011;Kulich et al, 2015;Sabharwal, 2013).…”